1. Field of the Invention
The present invention relates to a powered sliding device for a vehicle sliding door.
2. Description of the Related Art
Conventionally, powered sliding devices for a vehicle sliding door, wherein the sliding door is slid in the door closing direction and in the door opening direction by rotating a wire drum connected to the sliding door through a wire cable by the power of a motor have been well known.
In the powered sliding devices, there is one which uses a solenoid as a part. The solenoid is used in an electromagnetic clutch for transmitting the rotation of the motor to the wire drum or an electromagnetic brake for applying braking to the wire drum. It cannot be said that the electromagnetic brake is an essential unit for the powered sliding device, but it is possible to comparatively easily improve the safety and the controllability of the sliding device by using the electromagnetic brake.
The electromagnetic clutch and electromagnetic brake cannot be operated when the wire of the solenoid is broken or the transistor for exciting the solenoid is damaged. In the case of the electromagnetic clutch, even if such a failure is caused, only the transmission of the rotation of the motor to the wire drum becomes impossible and no problem is caused in the manual door opening, and therefore, there is no trouble in the safety. However, when the electromagnetic brake is broken down, it becomes impossible to apply braking to the wire drum, and if the sliding door is slid by the motor power supposing that the electromagnetic brake can be used, the effect to the safety is produced.
Furthermore, a powered closing device wherein when the sliding door has moved in the door closing direction to a predetermined position, the latch to be engaged with the striker is rotated in the full-latch direction by the motor power, so that the sliding door is made in the full-latched state is also well known, and the powered closing device may be used together with the powered sliding device.
In the basic setting of the combination device, the sliding device takes charge of the movement from the door opening position of the sliding door to the half-latched position. Then, the closing device takes charge of the movement from the position a little before the half-latched position of the sliding door to the full-latched position. Thus, in the basic setting, between the position on this side and the half-latched position, the sliding device and the closing device are operated at the same time, and consequently, it is arranged that the sliding door moved by the sliding device can surely be passed to the closing device.
The first problem of the basic setting is that the sliding device and the closing device operate at the same time. When both devices operate at the same time, a large load is applied to the battery to cause sudden dropping of the voltage, and the operation of the sliding device and the closing device becomes unstable. Therefore, previously, the use of the strengthened electric system has become essential, and it has been inevitable for the device to be large-sized.
Furthermore, the second problem of the basic setting is that it is necessary to always move the sliding door to the half-latched position by the sliding device. In order to move the sliding door to the half-latched position, an unexpectedly strong force is necessary because of the effect of the reaction of the weather strip or the like. Therefore, the sliding device is also made large-sized.